In recent years, the fresh produce market has expanded as health-conscious consumers have demanded greater varieties and amounts of high quality fresh fruits and vegetables. Consequently, considerable efforts have been expended to ensure that losses due to spoilage or deterioration in quality of the produce are curtailed, so that consumers may enjoy the highest quality produce at the lowest possible price.
In particular, efforts have been directed at inhibiting the dark and unappealing color change known as "browning" which many fruits and vegetables suffer after being cut, scratched, or otherwise subjected to surface wounds during harvesting, packaging, or shipment. Browning, which is thought to result from the enzymatic oxidation of certain phenolic compounds present in the plant tissue, also occurs internally in uncut pineapple fruits. Internal browning is especially pronounced in fruit that has undergone cold storage during shipment. Because browning ruins the fresh quality of the harvested fruit over time, the marketable shelf life of the fruit is significantly decreased.
It is known in the art to treat fruit with heat (about 37.degree. C.) before packaging or after shipment at the retail market to inactivate the enzymes, e.g., polyphenoloxidase, responsible for browning. Unfortunately, it has been found that such heat treatment enhances fruit senescence or post-harvest ripening, thereby shortening shelf life. Additionally, such methods are not reliable or practical for large commercial shipments.
Alternatively, wax coatings have been employed to suppress the internal browning of fruit. However, it is difficult to apply such wax coatings to all portions of the fruit without using so much wax that the "breathing" of the fruit is not interfered with to an undesirable extent. Moreover, some of the waxes commonly used to coat certain fruits, are only partially effective in suppressing the internal browning of other fruits. For example, two commercial waxes commonly used to coat apples, peaches, plums, tomatoes and the like, namely DECCO 201 and FMC 705 (commercially available from Decco Tilbelt and FMC Corp. respectively), which contain mainly paraffin and polyethylene waxes, in addition to minor amounts of emulsifiers as stabilizers, are only partially effective in retarding internal browning in pineapples.